Support is requested for a Keystone Symposia meeting entitled Viruses and Human Cancer, organized by Charles R.M. Bangham, Thomas F. Schulz and Paul M. Lieberman. The meeting will be held in Big Sky, Montana from March 29 - April 3, 2015. In 1970, an authoritative book entitled Viruses and Cancer was published by Sir Christopher Andrews, one of the discoverers of influenza virus. On page 135 he wrote Despite these findings, there is no doubt that as regards the generality of cancers in man, and indeed in other mammals, there is no direct evidence that viruses are concerned. It is now estimated that about 20 percent of human cancers are caused by infectious agents, among them at least 7 viruses. The increasing appreciation of the role of viruses in cancer pathogenesis has not only already led to the development of two successful vaccines (against HBV and HPV) that prevent cancer, it has also directly contributed to many fundamental discoveries in cancer biology. In the last decade the understanding of virus-induced cancers has been accelerated by the extraordinary developments in genomics, epigenetics and RNA biology. To review this rapidly burgeoning field, this multidisciplinary symposium brings together experts in virology, oncology, immunology, genomics and genetics. The objective of the symposium is to explore how advances in cancer biology can inform the understanding of virus-induced cancers, and how viruses continue to reveal fundamental principles in cancer. Particular emphasis will be laid on the interaction between virus and host in persistent infections by oncogenic viruses. The meeting will cover examples of cancers where a viral cause is still under debate and the rapid development of technology for the detection of unknown viruses.